Answer:
It emits energy since to move from a higher energy level to a lower energy level or ground state, it must lose energy.
Which describes a chemical change? (Select all that apply.)
A new substance is created.
A phase change is occurring.
It is a permanent change.
It can be a physical change.
Explanation:
it is a permanent change
Answer: It is a permenat change
Explanation: Because you are creating it into something else and when it turns into that thing it stays like that permanatly.
Alka-Seltzer is pure NaHCO3
True or false?
Answer:
falso
Explanation:
A chemical reaction takes place in a closed system. The mass of the reactants before the reaction was grams. What must the mass of the products of the reaction be, according to the law of conservation of mass?
A. 35 grams B. 30 grams C. 70 grams D. 25 grams
Answer:
D. 25 grams
Explanation:
I think that's what the answer is
1. Oxygen was discovered by Joseph Priestley in 1774 when he heated mercury (II) oxide, HgO, to decompose it to form its constituent elements. How many moles of mercury (II) oxide are needed to produce 125 g of oxygen?
Given:
Unknown:
Mole ratio:
Solution:
2. In a blast furnace, iron (III) oxide is used to produce iron by the following (unbalanced) reaction:
Fe2O3(s) + CO(g) Fe(s) + CO2(g)
If 4000 g of Fe2O3 is available to react, how many moles of CO are needed?
Given:
Unknown:
Mole ratio:
Solution:
Final answer:
ugh pls help:(
Answer:
1. 7.81 moles HgO
2. n = mass/molar mass = (4000 g)/(159.69 g/mol) = 25.05 mol.
Explanation:
How many moles of mercury (II) oxide are needed to produce 125 g of oxygen?
2HgO ==> 2Hg + O2
125 g O2 x 1 mol O2/32 g x 2 mol HgO / mol O2 = 7.81 moles HgO
------------------------------------------------------------------------------------------------------------
If 4000 g of Fe2O3 is available to react, how many moles of CO are needed?
The no. of moles of CO are needed = 75.15 mol.
Fe₂O₃ + 3CO → 2Fe + 3CO₂,
It is clear that 1 mol of Fe₂O₃ reacts with 3 mol of CO to produce 2 mol of Fe and 3 mol of CO₂.
If 4.00 kg Fe₂O₃ are available to react, how many moles of CO are needed?
We need to calculate the no. of moles of 4.00 kg Fe₂O₃:
n = mass/molar mass = (4000 g)/(159.69 g/mol) = 25.05 mol.
Using cross multiplication:
1 mol of Fe₂O₃ need → 3 mol of CO to react completely, from stichiometry.
25.05 mol of Fe₂O₃ need → ??? mol of CO to react completely.
The no. of moles of CO are needed = (3 mol)(25.05 mol)/(1 mol) = 75.15 mol.
According to stoichiometry of the chemical equation, if 4000 g of iron oxide is available to react,25.04 moles of CO are needed.
What is chemical equation?Chemical equation is a symbolic representation of a chemical reaction which is written in the form of symbols and chemical formulas.The reactants are present on the left hand side while the products are present on the right hand side.
A plus sign is present between reactants and products if they are more than one in any case and an arrow is present pointing towards the product side which indicates the direction of the reaction .There are coefficients present next to the chemical symbols and formulas .
The first chemical equation was put forth by Jean Beguin in 1615.By making use of chemical equations the direction of reaction ,state of reactants and products can be stated. In the chemical equations even the temperature to be maintained and catalyst can be mentioned.
159.69 g iron oxide gives 28 g CO thus 4000 g iron oxide will give 4000×28/159.69=701.35 g which is 701.35/28=25.04 moles.
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Identify which of the following equations are balanced and which ones are not balanced
A. CH4 +202 —> CO2 + 2H20
B. 6CO2 + 6H2O—> C6H12O6+602
C. 2Na + H2O —> 2NaOH+ H2
Answer:
A. balancedB. UnblalancedC. UnbalancedExplanation:
The electronic transition in a hydrogen atom from n = 6 to n = 3 emits electromagnetic radiation having a higher frequency than a transition
from n = 5 to n = 3
help please ill do anything really!!!!!!!
Answer:
The first one is air the second is decreases the third is water the fourth is gas and the last is liquid.
Explanation:
Hope it helps.
John Dalton thought that atoms
1. Cannot be broken down further
2. Have no mass
3. Contain molecules
4. Are all composed of carbon
Answer:
cannot be broken down further
Why do you think dark surfaces absorb radiation better than light surfaces?
Your answer→ The lighter side absorbs less of the incident light, reflecting some of the energy. Darker materials also emit radiation more readily than light-colored materials, so they cool faster.
To solve this we must be knowing each and every concept related to radiation. Therefore, dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
What is radiation?According to the energy of the emitted particles, radiation is frequently classified as being either ionizing or non-ionizing. More than 10 eV is often carried by ionizing radiation, which is sufficient to ionize atoms as well as molecules and rupture chemical bonds.
The word refers to radiation having an energy level high enough to ionize atoms, or to remove electrons from atoms to produce ions. Whenever an electron is removed from an atom's electron shell, or, as we may say, when it is "tried to knock out," the action of ionization takes place. Dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
Therefore, dark surfaces absorb radiation better than light surfaces as dark surfaces absorbs light of all wavelengths.
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Substance whose smell changes in acidic or basic solutions
Answer:
Olfactory indicators
Explanation:
The substance whose odour changes in an acidic of basic medium are called olfactory indicators. In an olfactory indicator , smell varies depending on whether it is mixed with an acidic or basic solution.
Describe the difference between at atom and an ion in regards to their substaomic
particles
Answer:
difference between atom and ion
Explanation:
What is an Atom?
The smallest unit of matter. It is indivisible and consists of neutrons, electrons and protons. Atoms can take part in chemical reactions. Combination of atoms together forms molecule. Always the number of protons and electrons are equal. Independent life may or may not be feasible within a solution. Nucleus of the atom is formed by protons and neutrons. Surrounding the nucleus are the electrons.
What is an Ion?
Atoms where the electrons and protons are not equal are called ions. Ions are charged particles. They can be either positively charged ions or negatively charged ions. If an atom is charged electrically it is considered an ion. If an atom contains maximum number of electrons than protons, then it is called anion. If an atom contains maximum number of protons than electrons, then it is called cation. Independent existence in a solution. When an atom gains or loses electrons, ion is formed.
To make you understand how atom and ion are different from each other, here are the some major differences between atom and ion:
What is the mass % of acetone in a 1.85 M solution of acetone (MM = 58.08 g/mol) in water? The density of the solution is 0.971 g/mL.
A 1.85 M acetone solution (MM = 58.08 g/mol) with a density of 0.971 g/mL has a mass percent of acetone of 11.0%.
What is the mass percent?It refers to the mass of solute in 100 grams of solution.
Let's suppose we have 1 L of the solution.
Step 1: Calculate the mass of solute (acetone).We have a 1.85 M solution of acetone (MM = 58.08 g/mol). We will calculate the mass of acetone using the following expression for molarity.
M = mass acetone / MM acetone × liters solution
mass acetone = M × MM acetone × liters solution
mass acetone = 1.85 mol/L × 58.08 g/mol × 1 L = 107 g
Step 2: Calculate the mass of the solution.We have 1 L (1000 mL) of the solution with a density of 0.971 g/mL.
1000 mL × 0.971 g/mL = 971 g
Step 3: Calculate the mass percent of acetone.%acetone = (107 g/971 g) × 100% = 11.0 %
A 1.85 M acetone solution (MM = 58.08 g/mol) with a density of 0.971 g/mL has a mass percent of acetone of 11.0%.
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adjoa's gross salary for last month was ghs 4687.24. if ghs 421.78 was deducted from adjoa's salary pay,how much take home pay did adjoa earned this past month?
Since Ghs. 421.78 was deducted from Adjoa's salary pay, her take home pay is Ghs. 4265.46.
Given the following data:
Adjoa's gross salary = Ghs. 4687.24.Deduction = Ghs. 421.78Gross profit can be defined as the profit earned by a business after subtracting its cost of manufacturing and distributing goods from its total revenue (sales).
On a related note, gross salary is the amount of money earned by an individual before any deduction such as tax.
To find how much take home pay Adjoa earned this past month:
[tex]Take\;home = Gross\;salary - deduction\\\\Take\;home = 4687.24 - 421.78[/tex]
Take home = Ghs. 4265.46.
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What energy keeps the water cycle going?
Answer:
the the that keeps the water cycle going is heat
state why vulcanologist make predications about when a volcano will erupt
Answer:
They want to know how long it has been since it last erupted.
Explanation:
Scientists study a volcano's history to try to predict when it will next erupt. They also want to know the time span between its previous eruptions
Three rocks are rolling down a hill at the same speed. Rock 1 has a mass of 1 kg1 kg; rock 2 has a mass of 1.5 kg1.5 kg, and rock 3 has a mass of 3 kg3 kg. Which rock has the most kinetic energy?
Answer: The first one has the most kinetic energy. Why? traveling with the slowest speed comes with the faster stop withholding more energy in the stone
Explanation:
If the atomic mass of an atom is 16 and its atomic number is 7. how many
neutrons does it have?
Answer:
8
Explanation:
A solution is prepared by diluting 6.0 mL of a 7.6 x 10-4 g/mL solution to a total volume
of 10.0 mL. Calculate the concentration of the dilute solution.
Answer:
4.56 X 10^ -4 g/mL
Explanation:
A solution is prepared by diluting 6.0 mL of a 7.6 x 10-4 g/mL solution to a total volume of 10.0 mL. Calculate the concentration of the dilute solution.
(7.6 X10^-4 gm/m L) x( 6.0 m L ) = 45.6 X 10^-4 g
this is dissolved )in 10 m L=45.6 X 10^-4 g/ 10
4.56 X 10^ -4 g/mL
check
6/10 =0.6
4.56/7.6 = o.,6
How many atoms of Xe does 7.84 moles of Xe contain?
helppp! ill give brainliest
Can anyone tell me why I got this question wrong? I have no clue.
Answer:
what queastiion
Explanation:
Answer:
what is the question
Explanation:
...
Which pair of compounds has the same empirical formula? C_{3}*H_{8} and C_{3}*H. C_{2}*H_{2} and C_{2}*H C_{4}*H_{10} and C_{6}*H C_{4}*H_{10} and C_{2}*H_{5}
Considering the definition of empirical and molecular formula, the pair of compounds C₄H₁₀ and C₂H₅ has the same empirical formula.
The empirical formula is the simplest expression to represent a chemical compound and indicates the elements that are present and the minimum proportion in whole numbers that there are between their atoms. This formula is also known as the "minimum formula".
On the other side, the molecular formula is the chemical formula that indicates the number and type of different atoms present in the molecule. But unlike the chemical formula, it shows the actual number of atoms that make up a molecule.
In this case, you can observe that if you divide the amount of each element by 2 in compound C₄H₁₀, you get C₂H₅, which is the empirical formula of the compound.
Finally, the pair of compounds C₄H₁₀ and C₂H₅ has the same empirical formula.
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https://brainly.com/question/6960643Materials Visible Uniform Not Visible Non- Uniform State of Matter 1. Sugar and water 2. Oil and water 3. Vinegar and water 4. Salt and pepper 5. leaf and water
Answer:
1. Uniform, non visible
2. Visible, non uniform
3. Uniform, non visible
4. Visible, non uniform
5. Visible, non uniform
Explanation:
A heterogeneous mixture is simply any mixture that is not uniform in composition — it's a non-uniform mixture of smaller constituent parts. By contrast, a mixture that is uniform in composition is a homogenous mixture
visible state of matter is when you can easily difference two components of a mixture
non visible is when the state of the matter in the substance is not visible to the eye, it can't be differentiated
Calculate the number of days after the explosion for a sample of iodine-131 to go from 100%
iodine-131 to less than 1% iodine-131. Complete chart.
It will take 56 days to go from 100% iodine-131 to less than 1% iodine-131.
From the table, we can see that the half life of iodine-131 is 8 days. We can see that it takes 8 days to have 50% of iodine-131
After 16 days, we will have 25 % of iodine-131
After 24 days, we will have 12.5 % of iodine-131
After 32 days, we will have 6.25% of iodine-131
After 40 days, we will have 3.125% of iodine-131
After 48 days, we will have 1.5625% of iodine-131
After 56 days, we will have 0.78125% of iodine-131
After 56 days, the percentage of iodine-131 drops to less than 1%.
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Vitamin D is produced in the skin when 7-dehydrocholesterol reacts with UVB rays (ultraviolet B) having wavelengths between
270 nm and 300 nm. What is the energy range Emin < E< Emax of the UVB photons?
The energy range expected is 6.6 × 10^-19 J < E < 7.33 × 10^-19 J
The energy of the photon is given by;
E = hc/λ
E = energy of the photon
h = Plank's constant
c = speed of light
λ = wavelength of light
For the upper boundary range;
E = ?
h = 6.6 × 10^-34 Js
c = 3 × 10^8 m/s
λ = 270 × 10^-9
E = 6.6 × 10^-34 Js × 3 × 10^8 m/s / 270 × 10^-9
E = 7.33 × 10^-19 J
For the lower range;
E = ?
h = 6.6 × 10^-34 Js
c = 3 × 10^8 m/s
λ =300 × 10^-9
E = 6.6 × 10^-34 Js × 3 × 10^8 m/s / 300 × 10^-9
E = 6.6 × 10^-19 J
Hence, the energy range 6.6 × 10^-19 J < E < 7.33 × 10^-19 J
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Which of the following has more atoms?
One mole of zinc
One mole of gold
One mole of silver
One mole of magnesium
O They all have the same number of atoms
Answer:
They all have the same number of atoms
Explanation:
Which of the following has more atoms?
One mole of zinc
One mole of gold
One mole of silver
One mole of magnesium contians
O They all have the same number of atomst
a mole of anything contains Avogadros number of 6.022X10^23 things
which has the greatest number of thing? a dozen eggs, a dozen cookies, a dozen pizzas?
a dozen is a number means 12
a mole is a number that that means 6.022 X 10^23 you calculate the molar mass from the chemical formula, but every j mole contains 6.022X10^23
particles.
just like every dozen contains 12
so
They all have the same number of atoms
Select reason(s) why 1-hydroxy-2-methyl-5-isopropylbenzene is an incorrect systematic name for carvacrol.
a. If named with benzene as the parent, the methyl group needs to have the first locant in order to minimize the number of the third locant.
b. The substituents are not listed alphabetically.
c. If named with benzene as the parent, the hydroxyl group needs to have the first locant in order to minimize the number of the third locant.
d. The substituents are not listed in order of increasing mass.
The reason why 1-hydroxy-2-methyl-5-isopropylbenzene is not the correct systematic name for carvacrol is because the substituents are not listed alphabetically.
IUPAC nomenclature provides the correct and acceptable system of naming organic compounds which are internationally acceptable among scientists.
According to the rules of IUPAC nomenclature, compounds are named in alphabetical order. The names of the locants are ordered in such a way that they have the lowest number. Following IUPAC nomenclature, the correct name of the compound ought to be, 1-hydroxy-5-isopropyl-2-methylbenzene.
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What is the angle between adjacent sp hybrid orbitals?
Answer:
180 degrees
Explanation:
sp hybridization generates orbitals that overlap linearly, generating a straight line. This leads to an angle measurement of 180 degrees.
How many grams are in 0.990 mol of neon?
mass in grams:
Explanation:
Multiply the given moles times the molar mass of neon, 20.180 g/mol (periodic table).
Answer:
Multiply the supplied moles by 20.180 g/mol, the molar mass of neon (periodic table).
Explanation:
What is the sum of the atomic numbers of each element present in the reactants of the given formula?
2 NH3 + H2SO4 → (NH4)2SO4
Answer:
25
Explanation: They all add up to 25 Atoms
The atomic number of nitrogen is 7 and that of oxygen is 8. Atomic number of hydrogen is one and the atomic number of sulphur is 16. Then, the sum of atomic numbers of each element present in the reactants of the given formula is 32.
What is atomic number ?The atomic number of an atom is the number of electrons in its neutral state. This number is equal to the number of protons also. The modern periodic table classify all elements based on their atomic numbers.
The sum of number of protons and neutrons of an element is called its mass number. For the given formula, the elements present are H, O, N and S.
atomic number of H = 1
atomic numebr of N = 7
atomic number of O =8
atomic number of S = 16.
Then ,sum of atomic number s= 1 + 7 + 8 + 16 = 32.
Therefore, the sum of the atomic numbers of each element present in the reactants of the given formula is 32.
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